This study checks if a drug called IRL757 is safe and works well for people with Parkinson's disease (a brain disorder causing movement problems) who also have apathy (lack of interest). It compares IRL757 to a placebo (a fake treatment that looks like the real one but has no drug). Participants will take either IRL757 or the placebo for 12 weeks and visit the clinic 5 times for check-ups. After finishing the study, there will be a follow-up call 4 weeks later.

• The study lasts 12 weeks, with 5 clinic visits and a follow-up call.
• Participants may receive either the study drug IRL757 or a placebo.
• Eligibility requires having Parkinson's and apathy, among other criteria.

Participants must be between 50-90 years old, with specific health conditions and no major psychiatric issues. They must have a caregiver to assist with visits. This study is important to understand the safety and effectiveness of IRL757 for improving symptoms in Parkinson's patients with apathy.